Also fix a few bad links.
Change-Id: If04cdd312db24a827a3c958a9974c50ab148656c
Reviewed-on: https://go-review.googlesource.com/18979
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Fixes#13954
Change-Id: I4c01e9bb3fb08e8b9fa14d4c59b7ea824ba3f0c9
Reviewed-on: https://go-review.googlesource.com/18937
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Consider this code:
func f(*int)
func g() {
p := new(int)
f(p)
}
where f is an assembly function.
In general liveness analysis assumes that during the call to f, p is dead
in this frame. If f has retained p, p will be found alive in f's frame and keep
the new(int) from being garbage collected. This is all correct and works.
We use the Go func declaration for f to give the assembly function
liveness information (the arguments are assumed live for the entire call).
Now consider this code:
func h1() {
p := new(int)
syscall.Syscall(1, 2, 3, uintptr(unsafe.Pointer(p)))
}
Here syscall.Syscall is taking the place of f, but because its arguments
are uintptr, the liveness analysis and the garbage collector ignore them.
Since p is no longer live in h once the call starts, if the garbage collector
scans the stack while the system call is blocked, it will find no reference
to the new(int) and reclaim it. If the kernel is going to write to *p once
the call finishes, reclaiming the memory is a mistake.
We can't change the arguments or the liveness information for
syscall.Syscall itself, both for compatibility and because sometimes the
arguments really are integers, and the garbage collector will get quite upset
if it finds an integer where it expects a pointer. The problem is that
these arguments are fundamentally untyped.
The solution we have taken in the syscall package's wrappers in past
releases is to insert a call to a dummy function named "use", to make
it look like the argument is live during the call to syscall.Syscall:
func h2() {
p := new(int)
syscall.Syscall(1, 2, 3, uintptr(unsafe.Pointer(p)))
use(unsafe.Pointer(p))
}
Keeping p alive during the call means that if the garbage collector
scans the stack during the system call now, it will find the reference to p.
Unfortunately, this approach is not available to users outside syscall,
because 'use' is unexported, and people also have to realize they need
to use it and do so. There is much existing code using syscall.Syscall
without a 'use'-like function. That code will fail very occasionally in
mysterious ways (see #13372).
This CL fixes all that existing code by making the compiler do the right
thing automatically, without any code modifications. That is, it takes h1
above, which is incorrect code today, and makes it correct code.
Specifically, if the compiler sees a foreign func definition (one
without a body) that has uintptr arguments, it marks those arguments
as "unsafe uintptrs". If it later sees the function being called
with uintptr(unsafe.Pointer(x)) as an argument, it arranges to mark x
as having escaped, and it makes sure to hold x in a live temporary
variable until the call returns, so that the garbage collector cannot
reclaim whatever heap memory x points to.
For now I am leaving the explicit calls to use in package syscall,
but they can be removed early in a future cycle (likely Go 1.7).
The rule has no effect on escape analysis, only on liveness analysis.
Fixes#13372.
Change-Id: I2addb83f70d08db08c64d394f9d06ff0a063c500
Reviewed-on: https://go-review.googlesource.com/18584
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Now there are ARM downloads too.
Change-Id: I236381508c69d56748e672d184b92caa715e81ae
Reviewed-on: https://go-review.googlesource.com/18342
Reviewed-by: Andrew Gerrand <adg@golang.org>
The old link died; replace with an archive.org copy.
Fixes#13345.
Change-Id: Ic4a7fdcf258e1ff3b4a02ecb4f237ae7db2686c7
Reviewed-on: https://go-review.googlesource.com/18335
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Also reference the new Transport.ExpectContinueTimeout after the
mention of 100-continue.
Fixes#13721
Change-Id: I3445c011ed20f29128092c801c7a4bb4dd2b8351
Reviewed-on: https://go-review.googlesource.com/18281
Reviewed-by: Andrew Gerrand <adg@golang.org>
Slightly rephrased sentence to emphasize the contents of the
Unicode categories w/o repeating the full category name each
time.
Fixes#13414.
Change-Id: Icd32ff1547fa81e866c5937a631c3344bb6087c6
Reviewed-on: https://go-review.googlesource.com/18265
Reviewed-by: Rob Pike <r@golang.org>
The proper term is "untyped boolean".
Change-Id: Id871164190a03c64a8a8987b1ad5d8653a21d96e
Reviewed-on: https://go-review.googlesource.com/16135
Reviewed-by: Robert Griesemer <gri@golang.org>
The spec defines precise numeric constants which do not overflow.
Consequently, +/-Inf and NaN values were excluded. The case was not
clear for -0.0 but they are mostly of interest to determine the sign
of infinities which don't exist.
That said, the conversion rules explicitly say that T(x) (for a numeric
x and floating-point type T) is the value after rounding per IEEE-754.
The result is constant if x is constant. Rounding per IEEE-754 can
produce a -0.0 which we cannot represent as a constant.
Thus, the spec is inconsistent. Attempt to fix the inconsistency by
adjusting the rounding rule rather than letting -0.0 into the language.
For more details, see the issue below.
Open to discussion.
Fixes#12576.
Change-Id: Ibe3c676372ab16d9229f1f9daaf316f761e074ee
Reviewed-on: https://go-review.googlesource.com/14727
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The prose discussing composite literals referred to the composite
literal type with 'LiteralType', denoting the literal type's EBNF
production explicitly. Changed 'LiteralType' to 'literal type' to
remove the literal (no pun intended) connection and instead mean
the underlying type. Seems a simpler and more readable change
than referring to the underlying type everywhere explicitly.
Fixes#12717.
Change-Id: I225df95f9ece2664b19068525ea8bda5ca05a44a
Reviewed-on: https://go-review.googlesource.com/14851
Reviewed-by: Rob Pike <r@golang.org>
Fixes#12288.
For inclusion in the 1.5.1 release.
Change-Id: I9354b7eaa76000498465c4a5cbab7246de9ecb7c
Reviewed-on: https://go-review.googlesource.com/14382
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Start go1.6.txt with a note that nacl ports are no longer
restricted to pepper_41 and a record of the text/template change.
Change-Id: I21dda64aec113c35caf1d565f29e3aac8171480a
Reviewed-on: https://go-review.googlesource.com/14004
Reviewed-by: Rob Pike <r@golang.org>
This makes sure the release page in the release will mention the release.
Fixes#12102.
Change-Id: I36befd7dba7ba9e70ae3335e21c8841179ac4eff
Reviewed-on: https://go-review.googlesource.com/13490
Reviewed-by: Rob Pike <r@golang.org>
Saying "Power 64" was wrong for reasons I don't remember.
(Those reasons are why we stopped using GOARCH=power64.)
Change-Id: Ifaac78d5733bfc780df01b1a66da766af0b17726
Reviewed-on: https://go-review.googlesource.com/13675
Reviewed-by: Rob Pike <r@golang.org>
Make clear that this list is the list of supported systems
for binary distributions, and that other systems may be
able to build the distribution from source, in addition
to using gccgo.
Drop freebsd/arm from the list on this page.
We have never issued a binary distribution for freebsd/arm,
and we're not going to start in Go 1.5, since we don't even
have a working builder for it.
Drop freebsd/386 from the list on the page,
because we are unable to build binary distributions, per adg.
I think the wording here should probably be revised further,
but not now.
Change-Id: Ib43b6b64f5c438bfb9aa4d3daa43393f1e33b71f
Reviewed-on: https://go-review.googlesource.com/13690
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The SetOutput function has been there since Go 1.
Fixes#12162.
Change-Id: I66210374877581e42689f9943532141659a55ca7
Reviewed-on: https://go-review.googlesource.com/13637
Reviewed-by: Rob Pike <r@golang.org>
Fixes#12062
Updates #11961
The sRPC nameservice was removed in pepper 42. For Go 1.5 stipulate
that NaCl requires pepper 41 only.
Change-Id: Ic88ba342d41f673391efaa96fb581712fa10a0fd
Reviewed-on: https://go-review.googlesource.com/13341
Reviewed-by: Andrew Gerrand <adg@golang.org>
First step towards cleaning up the operator section - no language
changes. Specifically:
- Grouped arithmetic operations by types (integer, floating-point,
string), with corresponding h4 headings.
- Changed Operator precedence title from h3 to h4.
- Moved Integer Overflow section after integer operations and changed
its title from h3 to h4.
This puts things that belong together closer. No heading id's were
lost (in case of references from outside the spec).
Change-Id: I6b349ba8d86a6ae29b596beb297cc45c81e69399
Reviewed-on: https://go-review.googlesource.com/13143
Reviewed-by: Rob Pike <r@golang.org>
Missed in CL 13074.
Change-Id: Ic0600341abbc423cd8d7b2201bf50e3b0bf398a7
Reviewed-on: https://go-review.googlesource.com/13167
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Tracing functionality was moved from runtime/pprof to runtime/trace.
Change-Id: I694e0f209d043c7ffecb113f1825175bf963dde3
Reviewed-on: https://go-review.googlesource.com/13074
Reviewed-by: Rob Pike <r@golang.org>
This change allows the download page to redirect the user to
/doc/install?download=filename so the user can see installation
instructions specific to the file they are downloading.
This change also expands the "Test your Go installation" section
to instruct the user to create a workspace, hopefully leading
to less confusion down the line.
It also changes the front page download link to go directly
to the downloads page, which will in turn take them to the
installation instructions (the original destination).
This is related to this change to the tools repo:
https://golang.org/cl/13180
Change-Id: I658327bdb93ad228fb1846e389b281b15da91b1d
Reviewed-on: https://go-review.googlesource.com/13151
Reviewed-by: Chris Broadfoot <cbro@golang.org>
I walked through the steps for a contribution but ended up
with an error when doing "git mail" because I didn't have a
signed agreement.
Added a section to check for or create one through Gerrit right
after the user has created the account and logged in.
Moved some info from copyright section to the new section.
Change-Id: I79bbd3e18fc3a742fa59a242085da14be9e19ba0
Reviewed-on: https://go-review.googlesource.com/13062
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
The spec didn't specify several aspects of expression switches:
- The switch expression is evaluated exactly once.
- Switch expressions evaluating to an untyped value are converted
to the respective default type before use.
- An (untyped) nil value is not permitted as expression switch
value. (We could permit it relatively easily, but gc doesn't,
and disallowing it is in symmetry with the rules for var decls
without explicit type and untyped initializer expressions.)
- The comparison x == t between each case expression x and
switch expression value t must be valid.
- (Some) duplicate constant case expressions are not permitted.
This change also clarifies the following issues:
4524: mult. equal int const switch case values should be illegal
-> spec issue fixed
6398: switch w/ no value uses bool rather than untyped bool
-> spec issue fixed
11578: allows duplicate switch cases -> go/types bug
11667: int overflow in switch expression -> go/types bug
11668: use of untyped nil in switch -> not a gc bug
Fixes#4524.
Fixes#6398.
Fixes#11668.
Change-Id: Iae4ab3e714575a5d11c92c9b8fbf027aa706b370
Reviewed-on: https://go-review.googlesource.com/12711
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Also make the spelling consistent in asm.html
Change-Id: Ifa751eee288fe0634cd317eb827f3e408b199620
Reviewed-on: https://go-review.googlesource.com/12501
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This is a corner case but it is suggested we call it out.
Fixes#11798.
Change-Id: I2ddb5b363cd2921666dbf03bbf98107697ca40e5
Reviewed-on: https://go-review.googlesource.com/12460
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The document `doc/go_spec.html` uses "preceeding" instead of the word
"preceding" in one place.
Fixed another occurrence in `src/go/types/typexpr.go`.
Change-Id: Ic67f62026b5c9d002c5c5632299f14ecac8b02ae
Reviewed-on: https://go-review.googlesource.com/12354
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Also add a link to a couple of the talks from GopherCon 2015.
Change-Id: I11e1c550e999553163d3fb5e900f167c849ce33f
Reviewed-on: https://go-review.googlesource.com/12287
Reviewed-by: Andrew Gerrand <adg@golang.org>
Also use more consistent language for the new build options.
Change-Id: I88cbe200c13f452713be73d2e00337ddb793b8c6
Reviewed-on: https://go-review.googlesource.com/12172
Reviewed-by: Rob Pike <r@golang.org>
This is the first mention of the fmt package in the changes list.
Change-Id: I5d378d8707e6735e0e590527db4196b517fefd72
Reviewed-on: https://go-review.googlesource.com/12198
Reviewed-by: Andrew Gerrand <adg@golang.org>
Still to do: ARM64 and PPC64. These architectures are woefully underdocumented.
Change-Id: Iedcf767a7e0e1c931812351940bc08f0c3821212
Reviewed-on: https://go-review.googlesource.com/12110
Reviewed-by: Russ Cox <rsc@golang.org>
The previous commit (git 2ae77376) just did golang.org. This one
includes golang.org subdomains like blog, play, and build.
Change-Id: I4469f7b307ae2a12ea89323422044e604c5133ae
Reviewed-on: https://go-review.googlesource.com/12071
Reviewed-by: Rob Pike <r@golang.org>
The one in misc/makerelease/makerelease.go is particularly bad and
probably warrants rotating our keys.
I didn't update old weekly notes, and reverted some changes involving
test code for now, since we're late in the Go 1.5 freeze. Otherwise,
the rest are all auto-generated changes, and all manually reviewed.
Change-Id: Ia2753576ab5d64826a167d259f48a2f50508792d
Reviewed-on: https://go-review.googlesource.com/12048
Reviewed-by: Rob Pike <r@golang.org>
The architecture-specific details will be updated and expanded in
a subsequent CL (or series thereof).
Update #10096
Change-Id: I59c6be1fcc123fe8626ce2130e6ffe71152c87af
Reviewed-on: https://go-review.googlesource.com/11954
Reviewed-by: Russ Cox <rsc@golang.org>
Don't know why, but git deleted the previous version of this change.
This is the same change as https://go-review.googlesource.com/11884,
which I will now abandon, with a couple of fixes.
Almost all done now. Could use help with the TODOs.
Major missing piece is the trace command. Vendoring
section is also weak, but it's also undocumented elsewhere.
Change-Id: I5d8556b23aa6628eb7bf0e330d4dd8d4ac2157c5
Reviewed-on: https://go-review.googlesource.com/11887
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Also add words about the assembler.
Change-Id: I9bd8cc88076f06b0eef36a07f57d1ad5d9261d8d
Reviewed-on: https://go-review.googlesource.com/11853
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Everything in the library but crypto and net.
Change-Id: I89b21b9621e6d338fa1891da0eabba5d7d2fe349
Reviewed-on: https://go-review.googlesource.com/11820
Reviewed-by: Russ Cox <rsc@golang.org>
No need to update the date; this is not a spec change.
Change-Id: I10a31234ed985c59e5d9b5328664a36661cef31e
Reviewed-on: https://go-review.googlesource.com/11531
Reviewed-by: Andrew Gerrand <adg@golang.org>
Just a copy, other than adding a header, preparatory to preparing the release notes.
Change-Id: Ia4dc27777b96b1e898d9873e7d38e6e795057698
Reviewed-on: https://go-review.googlesource.com/11474
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This sometime worries new contributors.
Hopefully mentioning it here will help.
Fixes#11300.
Change-Id: Ica7f10d749731704ac6a2c39c7dcba389996011e
Reviewed-on: https://go-review.googlesource.com/11236
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This also includes some other minor updates to the documentation.
Change-Id: Iafab353727d7622d125b97fbdeaa81525b7a92aa
Reviewed-on: https://go-review.googlesource.com/11123
Reviewed-by: Yves Junqueira <yves.junqueira@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
When reading along the article, the extra code added in the final
version is not explained. The main function calls flag.Parse(), for
example, which will cause an error, unless the readers looks at the
entirety of final.go to see the import added.
The file shown to the users no longer has the extra flags. The testing
code is now in a patch that gets applied to final.go in order to create
final-test.go. This is the file that will be used to test the code,
matching final.go as much as possible.
Change-Id: I022f5f6c88e107c8ba5623661d74a8d260d05266
Reviewed-on: https://go-review.googlesource.com/11061
Reviewed-by: Andrew Gerrand <adg@golang.org>
Suggested by mdempsky (see also issue #11161).
Change-Id: I1ab28febe19b7a092029499015073ce8749b4d99
Reviewed-on: https://go-review.googlesource.com/10960
Reviewed-by: Ian Lance Taylor <iant@golang.org>
These were found by grepping the comments from the go code and feeding
the output to aspell.
Change-Id: Id734d6c8d1938ec3c36bd94a4dbbad577e3ad395
Reviewed-on: https://go-review.googlesource.com/10941
Reviewed-by: Aamir Khan <syst3m.w0rm@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reflect the process changes where AUTHORS and CONTRIBUTORS
files are updated automatically based on commit logs
and Google committers no longer need to do it manually
on the first contributors.
The documentation update will help to avoid requests to be
added from new contributors.
Change-Id: I67daae5bd21246cf79fe3724838889b929bc5e66
Reviewed-on: https://go-review.googlesource.com/10824
Reviewed-by: Rob Pike <r@golang.org>
I think it's worth mentioning.
But the final decision is up to you.
Change-Id: I3959132600ecc554988524ede73a7f6e8eac8353
Reviewed-on: https://go-review.googlesource.com/10551
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
- no "visible" change to spec but for updated date
- retired several outdated TODO items
- filed non-urgent issues 10953, 10954, 10955 for current TODOs
Change-Id: If87ad0fb546c6955a6d4b5801e06e5c7d5695ea2
Reviewed-on: https://go-review.googlesource.com/10382
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This CL removes the remaining visible uses of the "architecture letter" concept.
(They are no longer in tool names nor in source directory names.)
Because the architecture letter concept is now gone, delete GOCHAR
from "go env" output, and change go/build.ArchChar to return an
error always.
The architecture letter is still used in the compiler and linker sources
as a clumsy architecture enumeration, but that use is not visible to
Go users and can be cleaned up separately.
Change-Id: I4d97a38f372003fb610c9c5241bea440d9dbeb8d
Reviewed-on: https://go-review.googlesource.com/10289
Reviewed-by: Rob Pike <r@golang.org>
This is a duplicate of CL 9491.
That CL broke the build due to pprof shortcomings
and was reverted in CL 9565.
CL 9623 fixed pprof, so this can go in again.
Fixes#10659.
Change-Id: If470fc90b3db2ade1d161b4417abd2f5c6c330b8
Reviewed-on: https://go-review.googlesource.com/10212
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The spec explains later in the "Operator precedence" section that *
has a higher precedence than +, but the current production rule
requires that "1 + 2 * 3" be parsed as "(1 + 2) * 3", instead of the
intended "1 + (2 * 3)".
The new production rule better matches cmd/internal/gc/go.y's grammar:
expr:
uexpr
| expr LOROR expr
| expr LANDAND expr
| ...
Fixes#10151.
Change-Id: I13c9635d6ddf1263cafe7cc63e68f3e5779e24ba
Reviewed-on: https://go-review.googlesource.com/9163
Reviewed-by: Robert Griesemer <gri@golang.org>
In the Slices section of Effective Go, the os package's File.Read
function is used as an example. Unfortunately the function signature
does not match the function's code in the example, nor the os package's
documentation. This change updates the function signature to match
the os package and the pre-existing function code.
Change-Id: Iae9f30c898d3a1ff8d47558ca104dfb3ff07112c
Reviewed-on: https://go-review.googlesource.com/9845
Reviewed-by: Rob Pike <r@golang.org>
Change-Id: I70dfc2bad13c513c376c7c41058774b40af73dce
Reviewed-on: https://go-review.googlesource.com/9775
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
Solaris, like Windows, NetBSD and OpenBSD, uses macros for stdin, stdout,
and stderr. Cgo can't access them without getters/setters written in
C. Because of this we disable affected tests like for the other platforms.
Updates #10715.
Change-Id: I3d33a5554b5ba209273dbdff992925a38a281b42
Reviewed-on: https://go-review.googlesource.com/8264
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This reverts commit c26fc88d56.
This broke pprof. See the comments at 9491.
Change-Id: Ic99ce026e86040c050a9bf0ea3024a1a42274ad1
Reviewed-on: https://go-review.googlesource.com/9565
Reviewed-by: Daniel Morsing <daniel.morsing@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Package time already has enough inherently flaky tests covering its
behavior. No need for more of them.
Fixes#10632.
Change-Id: I1229e9fcc2e28ba2c9b0b79f73638e35dbbe8bbf
Reviewed-on: https://go-review.googlesource.com/9517
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The heap statistics were only written if asked for a profile with debug > 0,
but that also prints a stack trace for each profile line, which is comparatively
much noisier. The statistics are short enough and separate enough
(they only appear at the end) and useful enough that we can print them
always.
This means that people using -test.memprofile in tests will get a memory
profile with statistics included now. Pprof won't care, but if people care to
look, the numbers will be there.
This avoids the need for hacks like using -memprofilerate=1 to find
the number of allocations.
Change-Id: I10a4f593403d0315aad11b37c6e554b734caa73f
Reviewed-on: https://go-review.googlesource.com/9491
Reviewed-by: David Chase <drchase@google.com>
github.com/kr/goven says it's deprecated and anyway
it would be preferable to point users to a standard Go tool.
Change-Id: Iac4a0d13233604a36538748d498f5770b2afce19
Reviewed-on: https://go-review.googlesource.com/8969
Reviewed-by: Minux Ma <minux@golang.org>
This avoids a race condition with go1.go wanting to examine files in
the current directory with filepath.Walk(".", walkFn).
Fixes#10497.
Change-Id: I2159f40a08d1a768195dbb7ea3c27e38cf9740bb
Reviewed-on: https://go-review.googlesource.com/9110
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The tests in doc/progs appear to have been originally written
for use with the old test driver. At some later point,
they acquired their own test driver.
Both ran tests in serial.
This CL rewrites the current test driver in Go,
runs tests concurrently, and cleans up
historical artifacts from the old drivers.
The primary motivation is to speed up all.bash.
On my laptop, using tip, this CL reduces doc/progs test
wall time from 26s to 7s. The savings will remain
even when the compiler gets faster. Using Go 1.4,
this CL reduces test wall time from 15s to 4s.
Change-Id: Iae945a8490222beee76e8a2118a0d7956092f543
Reviewed-on: https://go-review.googlesource.com/8410
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
to map element keys
Composite literals containing element values that are themselves composite
literals may leave away the element's literal types if they are identical
to the enclosing composite literal's element type.
(http://golang.org/ref/spec#Composite_literals)
When we made this change, we forgot to apply the analogous rule to map
literal keys. This change generalizes that rule. Added more examples,
including one showing the recursive application of the elision rules.
This is a fully backward-compatible language change. It was discussed
some time back.
Fixes#8589.
To be submitted once all compilers accept the extension.
Change-Id: I4d45b64b5970f0d5501572945d5a097e64a9458b
Reviewed-on: https://go-review.googlesource.com/2591
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
